L-2-Hydroxyglutarate sensitizes ferroptosis through ATF3/CHAC1-mediated glutathione degradation in hepatocellular carcinoma

Abstract

Ferroptosis is an iron-dependent form of regulated cell death driven by lipid peroxidation and glutathione (GSH) depletion and represents a therapeutic vulnerability in hepatocellular carcinoma (HCC). While canonical ferroptosis regulation centers on cystine uptake and GPX4-mediated GSH utilization, the endogenous metabolic pathways governing ferroptosis sensitivity in liver tumors remain incompletely understood. Here, using a metabolic-scale CRISPR activation screen integrated with transcriptomic and metabolomic analyses, we identify L-2-hydroxyglutarate dehydrogenase (L2HGDH) as a potent antagonist of ferroptosis in HCC. We demonstrate that L2HGDH is frequently suppressed in liver tumors, leading to pathological accumulation of its substrate L-2-hydroxyglutarate (L2HG). Elevated L2HG sensitizes HCC cells to ferroptosis both in vitro and in vivo. Mechanistically, L2HG acts as a metabolic-epigenetic regulator that inhibits 2-oxoglutarate-dependent dioxygenases, induces histone hypermethylation, and remodels chromatin accessibility to activate an ATF3-dependent transcriptional program. This program induces the glutathione-degrading enzyme CHAC1, thereby accelerating GSH degradation to 5-oxoproline and disrupting redox homeostasis. Notably, L2HG-induced ferroptosis occurs independently of impaired cystine uptake, transsulfuration pathway activity, or increased GPX4-mediated GSH utilization, revealing a non-canonical ferroptosis mechanism driven by enhanced GSH catabolism. Consistent with these findings, genetic targeting of L2HGDH suppresses tumor growth, elevates L2HG levels, enhances GSH degradation, and promotes ferroptosis in HCC xenograft models. Collectively, our study identifies the L2HGDH-L2HG axis as a previously unrecognized metabolic checkpoint controlling ferroptosis sensitivity in liver cancer and uncovers glutathione degradation as a therapeutically exploitable vulnerability for ferroptosis-based treatment strategies in HCC. A metabolic-scale CRISPR Activation (CRISPRa) screen identifies L2HGDH as a ferroptosis antagonist. L2HG sensitizes HCC cells to ferroptosis through ATF3/CHAC1-mediated GSH degradation. L2HG promotes chromatin accessibility through histone hypermethylation for gene regulation. L2HGDH silencing inhibited tumor xenograft growth in vivo. A metabolic-scale CRISPR Activation (CRISPRa) screen identifies L2HGDH as a ferroptosis antagonist. L2HG sensitizes HCC cells to ferroptosis through ATF3/CHAC1-mediated GSH degradation. L2HG promotes chromatin accessibility through histone hypermethylation for gene regulation. L2HGDH silencing inhibited tumor xenograft growth in vivo. A metabolic environment (reduced L2HGDH expression and suppressed TCA cycle OGDH activity) prone to L2HG accumulation in HCC. L2HG increases ATF3/CHAC1 expression through histone hypermethylation to promote GSH degradation to 5-oxoproline (5OP) and induces ferroptosis. A metabolic environment (reduced L2HGDH expression and suppressed TCA cycle OGDH activity) prone to L2HG accumulation in HCC. L2HG increases ATF3/CHAC1 expression through histone hypermethylation to promote GSH degradation to 5-oxoproline (5OP) and induces ferroptosis.